Abstract The syntheses and characterization of a methoxo-bridged diiron (III) complex,[Fe 2 L Se 2 (μ-OCH 3) 2 (CH 3 OH) 2](1), and three mononuclear iron (III) complexes Bu 4 N [FeL Se 2](2), Bu 4 N [FeL Se′ L Se](3) and Bu 4 N [FeL S′ LS](4)[H 2 L Se= 2, 2′-selenobis (4, 6-di-tert-butylphenol), H 2 LS= 2, 2′-thiobis (4, 6-di-tert-butylphenol), H 2 L Se′= 3, 5-di- tert-butyl-2-hydroxyselenophenol, and H 2 LS′= 3, 5-di-tert-butyl-2-hydroxythiophenol] ...